UDP服务器/客户端

        UDP客户端源程序
        #include   <stdio.h>
        #include   <winsock2.h>
        #pragma   comment(lib,   "WS2_32.lib")

        #define   BUF_SIZE         1024
        #define   SERVER_IP       "127.0.0.1"
        #define   SERVER_PORT   5678

        int   main(int   argc,   char**   argv)
        {
                WSADATA   wsaData;
                SOCKET     socketC;
                SOCKADDR_IN   serverAddr;
                char   sendbuf[BUF_SIZE]   =   "Hello   UDP   World!";

                WSAStartup(MAKEWORD(1,1),   &wsaData);

                socketC   =   socket(AF_INET,   SOCK_DGRAM,   IPPROTO_UDP);

                serverAddr.sin_family   =   AF_INET;
                serverAddr.sin_port   =   htons(SERVER_PORT);
                serverAddr.sin_addr.s_addr   =   inet_addr(SERVER_IP);
       
                sendto(socketC,   sendbuf,   sizeof(sendbuf),   0,   (SOCKADDR*)&serverAddr,   sizeof(serverAddr));

                closesocket(socketC);

                WSACleanup();

                return 0:
        }


        UDP服务器端源程序
        #include   <stdio.h>
        #include   <winsock2.h>
        #pragma   comment(lib,   "WS2_32.lib")

        #define   BUF_SIZE         1024
        #define   SERVER_IP       "127.0.0.1"
        #define   SERVER_PORT   5678

        int   main(int   argc,   char**   argv)
        {
                WSADATA   wsaData;
                SOCKET     socketC;
                SOCKADDR_IN   serverAddr;
                char   recvbuf[BUF_SIZE];

                WSAStartup(MAKEWORD(1,1),   &wsaData);

                socketC   =   socket(AF_INET,   SOCK_DGRAM,   IPPROTO_UDP);

                serverAddr.sin_family   =   AF_INET;
                serverAddr.sin_port   =   htons(SERVER_PORT);
                serverAddr.sin_addr.s_addr   =   htonl(INADDR_ANY);

                bind(socketC,   (SOCKADDR*)&serverAddr,   sizeof(serverAddr));

                int   nRet   =   recvfrom(socketC,   recvbuf,   sizeof(recvbuf),   0,   0,   0);
                if   (nRet   >   0)
                        printf("%s   ",   recvbuf);

                closesocket(socketC);

                WSACleanup();

                return 0:
        }